There are plus and minus to both. What used to be that 5th wheels were always nicer interior than fifths is now a myth. Many of the TT mfg make them just as nice interior wise and the same sizes as fifth wheel.
There is more storage on a fifth but you do lose some of the bed so depending on what you bring with you either could be good. Water tanks can be just as big on TT as 5th now a days too so look around and you can throw that one out too.
There are better hitches out there now too that make towing a breeze. When towing a beast you should spend the money on one of the premiere hitches. If you do towing will not be that different. Don't spend the money and yes you will have the doesn't tow well scenario happening especially on the large units.
Bottom line is look around and be open minded and other than the extra storage under the pin area of a fifth the rest of a TT can give you the same comforts for a lot less dollars.